A method for automatically controlling camber of a plate mill
By optimizing the billet heating and rolling process, and combining it with an automatic control system, problems such as mismatched roll cycles and misaligned steel plates during the rolling process of medium and heavy plate mills have been solved, effectively preventing sickle bends and improving production stability and equipment utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANGANG STEEL CO LTD
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies are insufficient to effectively solve the camber problem caused by improper roll cycle matching, misalignment and bite of steel plates, and stiffness deviation on both sides of the mill during the rolling process of medium and heavy plate mills. Furthermore, they also result in equipment damage and low production efficiency.
By optimizing the billet heating process, rolling specifications, and roll configuration, and combining them with an automatic control system, the billet temperature uniformity control, roll gap adjustment, and automatic compensation functions are achieved, ensuring uniform deformation and consistent rolling force of the steel plate during the rolling process.
It effectively reduced the incidence of sickle-shaped bending, improved equipment stability and production efficiency, reduced the spot rate to less than 0.5%, and reduced equipment damage and labor intensity.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal pressure processing, and specifically relates to an automatic control method for sickle bending in medium and heavy plate rolling mills. Background Technology
[0002] With the rapid development of the national economy, the market demand for heavy plate steel products is constantly increasing. Sickle bending is a common quality defect in the hot rolling production of heavy plates. Causes such as wedge-shaped incoming material, roll tilting, temperature deviations on both sides of the rolled piece, alignment problems with the side guide plates, and stiffness deviations on both sides of the stand can lead to sickle bending in the steel plate during rolling. This significantly harms the stability of rolling production. Minor issues include shortening the plate length compared to the design standard and excessive edge cutting damage, affecting the plate yield. More serious issues can lead to frame scraping, equipment shutdowns, plate scrap, equipment damage, and other accidents, thereby reducing equipment operating rate and production efficiency. Therefore, preventing sickle bending in the production of heavy plates is of paramount importance. Currently, there are two common measures taken in medium and heavy plate production lines to address the camber problem during rolling. One is to use a "clamping" method, where the steel plate is clamped from the moment it is bitten in until the centering device is ejected, to prevent deviation and the formation of camber. The other is for operators to observe the thickness and curvature of the steel plate on both sides through monitoring cameras and manually adjust the roll gap based on their experience. Both methods can reduce camber formation to some extent, but they cannot effectively solve the problem and have many drawbacks. The first method, relying on constant clamping by the pusher, is prone to damaging the centering equipment. The second method depends entirely on operator experience, resulting in poor control accuracy. Therefore, to address the camber problem in medium and heavy plate rolling mills, a systematic optimization of the rolling process is needed. This optimization should reduce labor intensity, improve control precision, and lower production costs without damaging equipment, thereby resolving the widespread camber quality issue in rolled products.
[0003] Compared with existing technologies: To date, there has been very little research, both domestically and internationally, on methods for controlling camber in medium and heavy plate rolling mills. Prior to this invention, patent publication number CN 202110000908.2 disclosed a method for controlling camber in medium and heavy plates. This method calculates the predicted bounce deviation of the operating side and drive side for each rolling pass by adjusting the rolling schedule and the stiffness measurement curves on both sides of the rolling mill; then, based on the finished product specifications and rolling passes, it calculates the automatic adjustment of the roll gap inclination for each pass; finally, the adjusted inclination is applied to the set values of the hydraulic cylinders on the operating side and drive side before the steel bites. Its core logic still uses the rolling force deviation control method on the drive side and the switching side to achieve rolling force deviation adjustment. However, due to problems such as axial movement of the rolls during the rolling process, misalignment of the steel plate during biting, increased stiffness deviation on both sides of the rolling mill, and reverse lateral bending of the steel plate in adjacent passes, the improvement effect of this method is not very significant in field applications.
[0004] The methods for controlling camber in medium and heavy plate rolling mills disclosed in the above patent documents, while solving problems such as reducing the spot rate of steel plates and decreasing downtime caused by camber, are not very effective in improving the rolling process due to issues such as axial movement of rolls, misalignment and biting of steel plates, increased stiffness deviation on both sides of the mill, and reverse lateral bending of steel plates in adjacent passes. Furthermore, the methods do not clearly address the thickness and width spacing of the steel plates. The technical solution provided by this invention effectively overcomes these shortcomings. It solves the problem of camber in steel plates with a thickness of 5-60mm and a width of 3500mm or less, caused by factors such as incoming material wedge shape, roll tilting, temperature deviation on both sides of the rolled piece, side guide plate alignment issues, and stiffness deviation on both sides of the mill stand, through reasonable heating, rolling, and straightening processes. Summary of the Invention
[0005] The purpose of this invention is to overcome the aforementioned technical problems and deficiencies, and to provide an automatic control method for camber in medium and heavy plate rolling mills. This method solves the problem of camber that may occur in steel plates with a thickness of 5-60mm and a width of 3500mm during the rolling process, caused by factors such as unreasonable roll cycle matching, misalignment and biting of the steel plate, and increased stiffness deviation on both sides of the rolling mill.
[0006] The objective of this invention is achieved through the following technical solution:
[0007] This invention provides an automatic control method for the sickle bend of medium-thick plates, comprising the following steps: 1) Billet Heating: The billet is fed into a walking beam furnace for heating. The billet passes through the preheating section, heating section and soaking section in sequence before exiting the furnace. The temperature range of the heating section and soaking section is 1190-1270℃. The total time in the heating section and soaking section is controlled to be 3-4 hours. The air-fuel ratio is controlled to be 1:2.1-2.3. At the same time, some of the burners in the upper part of the soaking section are closed to ensure that the temperature of the upper surface of the billet is 10-20℃ higher than that of the lower surface. (The soaking and heating sections provide high-temperature heating to ensure the temperature uniformity of all parts of the billet and improve the uniformity of transverse and longitudinal metal flow on both sides and at all positions of the steel plate. At the same time, the air-fuel ratio is controlled and some of the nozzles in the upper part of the soaking section are closed to ensure that the temperature of the upper surface of the billet is 10-20℃ higher than that of the lower surface. This avoids the lower surface of the billet being affected by the water beam at the bottom of the furnace, which would result in a lower temperature on the lower surface and affect the uniformity of rolling deformation of the upper and lower surfaces.)
[0008] 2) Rolling: The heated billet is rolled; the steel rolling production scheduling principle and the roll crown configuration are optimized to determine the steel plate rolling specifications as follows: When 0.2mm ≤ roll crown ≤ 0.3mm, the steel plate specifications are: thickness 15~60mm, width 2200~3000mm; when 0.1mm ≤ roll crown < 0.2mm, the steel plate specifications are: thickness 15~60mm, width within 3500mm, or the steel plate specifications are: thickness greater than or equal to 5mm and less than 15mm, width less than 2200mm; when 0mm ≤ roll crown < 0.1mm, the steel plate specifications are: thickness 5~60mm, width within 3500mm; when -0.1mm ≤ roll crown < 0mm, the steel plate specifications are: thickness 10mm, width 150 ... ~60mm, width less than 3000mm (Optimizing the production roll cycle, mainly considering that in the rolling process of wide and thick plates, if the work roll surface has a negative convex shape, the gap between the two roll surfaces is relatively large compared to the two sides of the roll surface, and the plate on both sides tends to flow towards the middle. This type of roll shape can effectively prevent the occurrence of camber. Similarly, flat rolls are the next best, and positive convex rolls are the worst. At present, positive convex rolls are generally used for roll changing in production, and positive convexity has a significant impact on camber. In the initial rolling, positive convexity is used, which has a significant impact on production stability. As the working time of the rolls is extended and the wear of the rolls continues to increase, the roll surface shape gradually develops from positive convexity to negative convexity, the camber phenomenon tends to be alleviated, and the production stability is gradually improved. Based on this law, combined with on-site production and finite element simulation, this production plan is formulated).
[0009] Furthermore, in step 1), the thickness of the cast billet is less than 250 mm.
[0010] Furthermore, in step 1), the number of burners in the upper part of the heat exchange section that are turned off is 2 to 4 sets.
[0011] Furthermore, in step 2), the last pass is used as a leveling pass. Position control is adopted, and the roll gap of the leveling pass is increased by 1 to 5 mm based on the finished product thickness. The rolling force is 2000 to 5000 kN. The operator adjusts the roll gap of the leveling pass according to the plate shape and the deviation of the rolling force on both sides to ensure that the thickness on both sides of the intermediate billet is consistent.
[0012] Furthermore, in step 2), the clamping force of the pusher and the number of automatic clamping passes are determined according to the thickness of the steel plate. The clamping force of the pusher is set to 10-20 tons. At the same time, in the rolling mold, the first four passes of rolling steel plates of all thicknesses (thickness 5-60mm) and the last two passes of steel plates with a thickness of 10-60mm are maintained for automatic clamping by the pusher (the clamping process is adopted to ensure that the center line of the billet coincides with the center line of the pusher during the intermediate billet rolling process, so as to avoid the influence of the deviation of the rolling force on both sides and the generation of sickle bend).
[0013] Furthermore, in step 2), the AGC (Automatic Thickness Control) oil column deviation automatic compensation RAC (Sickle Curve) control function is finally put into operation. The AGC gain coefficient and the oil column deviation compensation amount are optimized. The AGC gain coefficient is increased to 2000-2500. For each pass reduction ≥10mm, the oil column deviation compensation is 0.15-0.25mm. For each pass reduction <10mm, the oil column deviation compensation is 0.05-0.1mm, ensuring the consistency of rolling force on both sides.
[0014] Furthermore, steel plates are produced using cast billets on a medium-thickness reciprocating rolling mill.
[0015] The above-mentioned heating and rolling process overcomes the shortcomings of existing technologies and solves the problem that steel plates with a thickness of 5-60mm and a width of 3500mm may develop camber during rolling due to factors such as axial movement of the rolls, misalignment and biting of the steel plate, increased stiffness deviation on both sides of the mill, and reverse lateral bending of the steel plate in adjacent passes. The spot rate of steel plates is reduced to less than 0.5%. The process optimization has a significant effect on improving equipment stability and reducing the spot rate.
[0016] The beneficial effects of this invention are: 1. Limit the temperature and time of the billet in the heating and soaking zones to ensure temperature uniformity in all parts of the billet and improve the uniformity of lateral and longitudinal metal flow on both sides and at all positions of the steel plate; at the same time, control the air-fuel ratio and close some nozzles in the upper part of the soaking zone to ensure that the temperature of the upper surface of the billet is 10-20℃ higher than that of the lower surface, so as to avoid the lower surface of the billet being affected by the water beam at the bottom of the furnace, which would result in a lower temperature of the lower surface and affect the uniformity of rolling deformation of the upper and lower surfaces.
[0017] 2. The process design of this invention is reasonable and optimizes the production roll cycle. It primarily considers that during the rolling of thick plates, if the work roll surface has a negative convex shape, the gap between the two roll surfaces is relatively large compared to the sides, causing the plate material on both sides to tend to flow towards the center. This roll shape effectively prevents camber. Similarly, flat rolls are the next best option, while positive convex rolls are the worst. Currently, positive convex rolls are commonly used for roll changes, and positive convexity has a significant impact on camber. Initially, positive convexity is used in rolling, which has a significant impact on production stability. As the working time of the rolls increases and the wear of the rolls continues to increase, the roll surface shape gradually develops from positive convexity to negative convexity, the camber phenomenon tends to be alleviated, and production stability is gradually improved. Based on this principle, combined with on-site production and finite element simulation, this production scheduling plan was developed.
[0018] 3. Based on the traditional rolling method, the last pass is used as a leveling pass. Position control is adopted. The operator adjusts the roll gap of the leveling pass according to the shape of the plate and the deviation of the rolling force on both sides to ensure that the thickness of the intermediate billet is consistent on both sides.
[0019] 4. A clamping process is adopted to ensure that the centerline of the billet coincides with the centerline of the pusher during the intermediate billet rolling process, avoiding the influence of rolling force deviation on both sides and the generation of camber. Finally, the AGC (Automatic Thickness Control) oil column deviation automatic compensation RAC (camber) control function is implemented to optimize the AGC gain coefficient and oil column deviation compensation amount to ensure the consistency of rolling force on both sides.
[0020] 5. By adopting the above-mentioned heating and rolling process, the shortcomings of the existing technology are overcome. The problem of high spot rates of steel plates caused by factors such as axial movement of the rolls, misalignment and biting of the steel plates, increased stiffness deviation on both sides of the mill, and reverse lateral bending of the steel plates in adjacent passes during the rolling process is solved. Detailed Implementation
[0021] The following examples are used to illustrate the content of the present invention. These examples are only general descriptions of the content of the present invention and do not limit the content of the present invention.
[0022] An automatic control method for the sickle bend of medium-thick plates, wherein the steel plate thickness is 5-60mm and the width is less than 3500mm, and the plate is produced on a medium-thick plate reciprocating rolling mill using a billet with a thickness of less than 250mm, includes the following steps: 1) Billet heating: The billet is fed into a walking beam furnace for heating. The billet passes through the preheating section, heating section and soaking section in sequence before exiting the furnace. The temperature range of the heating section and soaking section is 1190~1270℃. The total time in the heating section and soaking section is controlled at 3~4 hours. The air-fuel ratio is controlled at 1:2.1~2.3. At the same time, 2~4 sets of burners in the upper part of the soaking section are turned off to ensure that the temperature of the upper surface of the billet is 10~20℃ higher than that of the lower surface.
[0023] 2) Rolling: The heated billet is rolled; the steel rolling production scheduling principles and the roll crown configuration of the rolling mill are optimized to determine the steel plate rolling specifications as follows: When 0.2mm ≤ roll crown ≤ 0.3mm, the steel plate specifications are: thickness 15~60mm, width 2200~3000mm; when 0.1mm ≤ roll crown < 0.2mm, the steel plate specifications are: thickness 15~60mm, width within 3500mm, or the steel plate specifications are: thickness greater than or equal to 5mm and less than 15mm. The thickness is 5-60 mm, and the width is less than 2200 mm. When 0 mm ≤ roll crown < 0.1 mm, the steel plate specifications are: thickness 5-60 mm, width within 3500 mm; when -0.1 mm ≤ roll crown < 0 mm, the steel plate specifications are: thickness 10-60 mm, width less than 3000 mm. Furthermore, the last pass is designated as a leveling pass, with position control. The roll gap in the leveling pass is increased by 1-5 mm based on the finished product thickness, and the rolling force is 2000-5000 kN. Additionally, the pusher clamping force and clamping passes are determined based on the steel plate thickness, with the pusher clamping force set to 10-20 tons. Simultaneously, within the rolling mold, the first four passes for rolling all thicknesses of steel plates and the last two passes for steel plates with a thickness of 10-60 mm or more are maintained for automatic pusher clamping. Finally, the AGC (Automatic Thickness Control) oil column deviation automatic compensation RAC (Sickle Curve) control function was implemented. The AGC gain coefficient and oil column deviation compensation amount were optimized. The AGC gain coefficient was increased to 2000-2500. For a pass reduction of ≥10mm, the oil column deviation compensation was 0.15-0.25mm. For a pass reduction of <10mm, the oil column deviation compensation was 0.05-0.1mm.
[0024] Examples 1-6 Table 1 shows the heating regime for the steel billet; Table 2 shows the rolling method for the steel in the example.
[0025] Table 1 Heating regime of steel billets in the examples
[0026] Table 2 Rolling method of steel in the examples
[0027] Therefore, compared with the prior art, the purpose of this invention is to overcome the aforementioned technical problems and deficiencies, and to provide an automatic control method for camber in medium and heavy plate rolling mills. By optimizing the heating and rolling process, the shortcomings of the prior art are overcome, and the problem of camber that may occur in steel plates with a thickness of 5-60 mm and a width of 3500 mm during rolling is solved. This is due to factors such as axial movement of the rolls, misalignment and biting of the steel plate, increased stiffness deviation on both sides of the rolling mill, and reverse lateral bending of the steel plate in adjacent passes. The spot rate of steel plates is reduced to less than 0.5%. The process optimization has a significant effect on improving equipment stability and reducing the spot rate.
[0028] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. An automatic control method for sickle bend in a medium-thick plate rolling mill, characterized in that, Includes the following steps: 1) Billet heating: The billet is sent into the heating furnace for heating. The billet passes through the preheating section, heating section and soaking section in sequence before exiting the furnace. The temperature of the heating section and soaking section is 1190~1270℃. The total time in the heating section and soaking section is controlled in the furnace for 3~4 hours. The air-fuel ratio is controlled at 1:2.1~2.
3. At the same time, some burners in the soaking section are closed to ensure that the temperature of the upper surface of the billet is 10~20℃ higher than that of the lower surface. 2) Rolling: Rolling the heated billet; The steel plate rolling specifications are determined based on the crown of the rolls as follows: When 0.2mm ≤ roll crown ≤ 0.3mm, the steel plate specifications for production are: thickness 15~60mm, width 2200~3000mm; When 0.1mm≤roll crown<0.2mm, the steel plate specifications for production are: thickness 15~60mm, width within 3500mm, or the steel plate specifications for production are: thickness greater than or equal to 5mm and less than 15mm, width less than 2200mm. When 0mm ≤ roll crown < 0.1mm, the steel plate specifications for production are: thickness 5~60mm, width within 3500mm; When -0.1mm ≤ roll crown < 0mm, the steel plate specifications for production are: thickness 10~60mm, width less than 3000mm.
2. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, In step 1), the thickness of the cast billet is less than 250 mm.
3. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, In step 1), the thickness of the cast billet is less than 250 mm.
4. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, In step 1), the number of burners in the soaking zone that are turned off is 2 to 4.
5. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, In step 2), the last pass is used as a leveling pass, and position control is adopted. The roll gap of the leveling pass is increased by 1 to 5 mm based on the finished product thickness, and the rolling force is 2000 to 5000 kN.
6. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, In step 2), the first four passes of rolling steel plates with a thickness of 5-60mm and the last two passes of rolling steel plates with a thickness of 10-60mm are automatically clamped by a pusher.
7. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 5, characterized in that, In step 2), the clamping force of the pusher is set to 10-20 tons.
8. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, In step 2), the AGC oil column deviation automatic compensation sickle control function is adopted, and the AGC gain coefficient is increased to 2000~2500. For a pass reduction of ≥10mm, the oil column deviation compensation is 0.15~0.25mm, and for a pass reduction of <10mm, the oil column deviation compensation is 0.05~0.1mm.
9. The automatic control method for sickle bend in a medium-thick plate rolling mill according to claim 1, characterized in that, Steel plates are produced using cast billets on a medium-thickness reciprocating rolling mill.